全文获取类型
收费全文 | 13468篇 |
免费 | 1217篇 |
国内免费 | 416篇 |
专业分类
耳鼻咽喉 | 134篇 |
儿科学 | 243篇 |
妇产科学 | 216篇 |
基础医学 | 2048篇 |
口腔科学 | 161篇 |
临床医学 | 1567篇 |
内科学 | 2174篇 |
皮肤病学 | 571篇 |
神经病学 | 769篇 |
特种医学 | 672篇 |
外国民族医学 | 7篇 |
外科学 | 1132篇 |
综合类 | 842篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 787篇 |
眼科学 | 372篇 |
药学 | 1729篇 |
5篇 | |
中国医学 | 556篇 |
肿瘤学 | 1111篇 |
出版年
2024年 | 21篇 |
2023年 | 151篇 |
2022年 | 443篇 |
2021年 | 533篇 |
2020年 | 369篇 |
2019年 | 445篇 |
2018年 | 481篇 |
2017年 | 409篇 |
2016年 | 564篇 |
2015年 | 747篇 |
2014年 | 889篇 |
2013年 | 878篇 |
2012年 | 1333篇 |
2011年 | 1261篇 |
2010年 | 768篇 |
2009年 | 625篇 |
2008年 | 786篇 |
2007年 | 764篇 |
2006年 | 617篇 |
2005年 | 604篇 |
2004年 | 459篇 |
2003年 | 409篇 |
2002年 | 335篇 |
2001年 | 145篇 |
2000年 | 145篇 |
1999年 | 157篇 |
1998年 | 98篇 |
1997年 | 96篇 |
1996年 | 63篇 |
1995年 | 67篇 |
1994年 | 45篇 |
1993年 | 39篇 |
1992年 | 58篇 |
1991年 | 40篇 |
1990年 | 35篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 31篇 |
1986年 | 16篇 |
1985年 | 17篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1979年 | 8篇 |
1971年 | 7篇 |
1970年 | 7篇 |
1966年 | 6篇 |
1965年 | 4篇 |
1935年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Control of HIV-1 replication by RNA interference 总被引:15,自引:0,他引:15
52.
53.
Kim NJ Park SJ Choi SH Lee MS Choo EJ Kwak YG Woo JH Ryu J Jeong JY Kim YS 《Microbial drug resistance (Larchmont, N.Y.)》2005,11(3):260-265
To characterize the phenotypes and genotypes of erythromycin-resistant clinical isolates of Streptococcus pneumoniae in Korea and to evaluate the in vitro activity of telithromycin against these erythromycin-resistant isolates, we tested a total of 676 isolates of S. pneumoniae collected from 1997 to 2002 in a tertiary hospital in Seoul, Republic of Korea. MICs for erythromycin and telithromycin were determined by the agar dilution method. The macrolide resistance phenotypes of erythromycin-resistant isolates were determined by the erythromycin- clindamycin-rokitamycin triple disk (ECRTD) and MIC induction tests, whereas their macrolide resistance genotypes were determined by PCR for the erm(B), erm(A), subclass erm(TR), and mef genes. To discriminate between mef(A) and mef(E), PCR-restriction fragment length polymorphism (RFLP) analyses were performed. Of the 676 S. pneumoniae isolates, 459 (67.9%) were resistant to erythromycin. Of the 459 erythromycin-resistant isolates, 343 (74.7%) were assigned to the cMLS phenotype, 48 (10.4%) to the iMcLS phenotype, 4 (0.9%) to the iMLS phenotype, and 64 (14.0%) to the M phenotype. The erm(B) gene was detected in 251 (54.6%) isolates, the mef gene was detected in 64 (14.0%), and both the erm(B) and mef genes were detected in 144 (31.4%) isolates. All of the mef genes detected were identified as mef(E). Of the 459 erythromycin- resistant isolates, all but one were susceptible to telithromycin. The MIC(50)/MIC(90) to telithromycin of isolates carrying erm(B), mef(E), and both genes was 0.06/0.5 microg/ml, 0.03/0.125 microg/ml, and 0.5/1.0 microg/ml, respectively. Although the MICs of telithromycin for the erythromycin-resistant isolates varied according to genotype, telithromycin was very active against these erythromycin-resistant S. pneumoniae. 相似文献
54.
Min-Seok Rha Hye Won Jeong Jae-Hoon Ko Seong Jin Choi In-Ho Seo Jeong Seok Lee Moa Sa A Reum Kim Eun-Jeong Joo Jin Young Ahn Jung Ho Kim Kyoung-Ho Song Eu Suk Kim Dong Hyun Oh Mi Young Ahn Hee Kyoung Choi Ji Hoon Jeon Jae-Phil Choi Eui-Cheol Shin 《Immunity》2021,54(1):44-52.e3
- Download : Download high-res image (218KB)
- Download : Download full-size image
55.
了解TGFβ1基因对血管内皮细胞表达细胞外基质蛋白及与基质黏附力的影响。用DOTAP脂质体转染p MAMneo TGFβ1于原代培养的脐静脉内皮细胞,经G4 18筛选,TGFβ1表达经免疫荧光鉴定。Western blot确定 型胶原、纤黏连蛋白的表达,微管吸吮系统确定内皮细胞与基质的黏附力。结果表明生理情况下的内皮细胞能表达少量的TGFβ1及胶原、纤黏连蛋白。经G4 18筛选,外源性TGFβ1在血管内皮细胞中稳定表达,能显著提高胶原、纤黏连蛋白纤维的表达及细胞与基质的黏附。说明TGFβ1在血管组织工程中促进内皮细胞的黏附具有一定的应用价值。 相似文献
56.
Thymocyte-thymocyte interaction for efficient positive selection and maturation of CD4 T cells 总被引:2,自引:0,他引:2
Despite numerous reports on MHC class II expression by T cells from a wide spectrum of mammalian species including humans, the biological relevance of this phenomenon has never been tested with appropriately designed animal models. To address this issue, we developed mouse models in which immature thymocytes are the only positively selecting antigen-presenting cells in the thymus. In these mice, CD4+ T cells were generated with the appropriate maturation phenotype and showed a diverse repertoire of TCR Vbetas. The CD4+ T cells were functionally competent, mediating effective allogeneic responses that involved polyclonal TCR Vbetas. These results suggest that the thymocyte-thymocyte (T-T) interaction operates as an independent pathway for CD4+ T cell selection in the thymi of species with MHC II-positive thymocytes. This T-T interaction appears to be the basis for the generation of donor MHC-restricted CD4+ T cells in xenogeneic hosts. 相似文献
57.
58.
目的:探讨NF-κB的活性及iNOS基因表达在低氧性肺动脉高压(HPH)发病过程中的变化。方法:复制低氧性肺动脉高压大鼠模型,用免疫组化、原位杂交、半定量逆转录-聚合酶链式反应(RT-PCR)和Western blot等方法进行检测。结果:iNOS mRNA在腺泡内肺动脉(IAPA)的表达,低氧28 d(H28d)组染色强于正常(N)组、低氧5 d(H5d)组和低氧14 d(H14d)组。半定量RT-PCR证实低氧肺组织iNOS mRNA含量在H28d组分别是N组、H5d组和H14d组的2.1倍、1.9倍和1.8倍。H28d组肺组织NF-κB的核染色增多,I-κBα的含量在N组、H5d组和H14d组分别是H28d组的2.7倍、2.8倍和2.5倍。结论:在HPH中NF-κB的激活可能与低氧肺血管构建及iNOS mRNA的表达有关。 相似文献
59.
Ru YX Wang HJ Yang BX Liu JH Li ZQ Li CW Wang JX Mi YC 《Ultrastructural pathology》2005,29(5):341-347
The objective of this study was to investigate the ultrastructural characteristics of hybrid acute leukemia (HAL). Fifteen cases of HAL were studied by transmission electron microscopy (TEM), focusing on organelles and myeloperoxidase (MPO) reaction of leukemic cells. By TEM, 5 out 15 cases of HAL were consistent with immunophenotyping (3 cases of biphenotypic type, and 2 cases of biclonal type with granulocytes and lymphocytes); 2 cases were suspected as HAL. On other hand, 5 cases of HAL were assigned to ALL, and 2 cases were misinterpreted as M5a and 1 as M4b. Most of the blast cells of biphenotypic HAL showed lymphoid features, except some cases containing MPO positive granules in blasts, while a few cases exhibited monocytic or nonspecific features. TEM offers advantages in the diagnosis of biclonal type HAL and biphenotypic HAL positive for MPO. However, it is difficult to differentiate MPO-negative cases of biphenotypic HAL from ALL and a few cases may be misinterpreted as M5 by TEM. 相似文献
60.
Effect of ketamine on apoptosis by energy deprivation in astroglioma cells using flow cytometry system 总被引:3,自引:0,他引:3
Apoptosis is a programmed, physiologic mode of cell death that plays an important role in tissue homeostasis. As for the central nervous system, ischemic insults can induce pathophysiologic cascade of apoptosis in neurophils. Impairment of astrocyte functions during brain ischemia can critically influence neuron survival by neuronglia interactions. We aimed to elucidate the protective effect of ketamine on apoptosis by energy deprivation in astrocytes. Ischemic insults was induced with iodoacetate/ carbonylcyanide m-chlorophenylhydrazone (IAA/CCCP) 1.5 mM/20 microm or 150 microm/2 microm for 1 hr in the HTB-15 and CRL-1690 astrocytoma cells. Then these cells were reperfused with normal media or ketamine (0.1 mM) containing media for 1 hr or 24 hr. FITC-annexin-V staining and propidium iodide binding were determined by using flow cytometry. Cell size and granularity were measured by forward and side light scattering properties of flow cytometry system, respectively. An addition of ketamine during reperfusion increased the proportion of viable cells. Ketamine alleviated cell shrinkage and increased granularity during the early period, and ameliorated cell swelling during the late reperfusion period. Ketamine may have a valuable effect on amelioration of early and late apoptosis in the astrocytoma cells, even though the exact mechanism remains to be verified. 相似文献